Recently, semiconductor devices including capacitors using ferroelectric substances and high dielectric substances as the dielectric film are proposed. As a semiconductor device using a ferroelectric substance as the dielectric film of the capacitor, the FeRAM (Ferroelectric Random Access Memory) is noted. Such FeRAM is a nonvolatile memory characterized by high operation speed, low electric power consumption, good write/read durability, etc. and is promised to be further developed.
However, when a ferroelectric substance or a high dielectric substance is used as the ferromagnetic film, often hydrogen and water arrive at the dielectric film in steps after the dielectric film has been formed. When hydrogen and water arrives at the dielectric film of the capacitor, the metal oxide forming the dielectric film is reduced by the hydrogen, and the capacitor has the electric characteristic deteriorated.
As techniques for preventing the deterioration of the dielectric film by hydrogen and water, the technique of forming aluminum oxide film, covering the capacitor, and the technique of forming aluminum oxide film on the inter-layer insulation film formed on the capacitor are proposed. Aluminum oxide film has the function of preventing the diffusion of hydrogen and water. Accordingly, the proposed techniques can prevent the arrival of hydrogen and water at the dielectric film, and the deterioration of the dielectric film due to hydrogen and water can be prevented.
Following references disclose the background art.
[Patent Reference 1]
Specification of Japanese Patent Application Unexamined Publication No. Hei 11-233542
[Patent Reference 2]
Specification of Japanese Patent Application Unexamined Publication No. 2004-509479
However, in the proposed semiconductor devices, as the materials of the electrode pads, Al (aluminum), Al—Cu (aluminum-copper) alloys, etc. are used, and when testes, etc are made by touching probes to the electrode pads, often the electrodes pads are broken or deformed. In such cases, often cracks are made in even in the inter-layer insulation film present below the electrode pads. In this case, hydrogen and water intrude from the electrode pads into the inside of the semiconductor devices, and to the dielectric film of the capacitors. When the hydrogen and water arrive at the dielectric film of the capacitors, the metal oxide used as the dielectric film is reduced by hydrogen, and the electric characteristics of the capacitors are deteriorated.